问从运行nodejs的web钩子中得到正确的响应方式是什么？

EN

const express = require('express');
const {
  dialogflow,
  Image,
  SimpleResponse,
} = require('actions-on-google')

const bodyParser = require('body-parser');
const request = require('request');
const https = require("https");
const app = express();
const Map = require('es6-map');

// Pretty JSON output for logs
const prettyjson = require('prettyjson');
const toSentence = require('underscore.string/toSentence');

app.use(bodyParser.json({type: 'application/json'}));

// http://expressjs.com/en/starter/static-files.html
app.use(express.static('public'));

// http://expressjs.com/en/starter/basic-routing.html
app.get("/", function (request, response) {
  console.log("Received GET request..!!");
  //response.sendFile(__dirname + '/views/index.html');
  response.end("Response from my server..!!");
});

// Handle webhook requests
app.post('/', function(req, res, next) {
  console.log("Received POST request..!!");
  // Log the request headers and body, to aide in debugging. You'll be able to view the
  // webhook requests coming from API.AI by clicking the Logs button the sidebar.
  console.log('======Req HEADERS================================================');    
  logObject('Request headers: ', req.headers);
  console.log('======Req BODY================================================');    
  logObject('Request body: ', req.body);
  console.log('======Req END================================================');    

  // Instantiate a new API.AI assistant object.
  const assistant = dialogflow({request: req, response: res});

  // Declare constants for your action and parameter names
  //const PRICE_ACTION = 'price';  // The action name from the API.AI intent
  const PRICE_ACTION = 'revenue';  // The action name from the API.AI intent
  var price = 0.0

  // Create functions to handle intents here
  function getPrice(assistant) {
    console.log('** Handling action: ' + PRICE_ACTION);
    let requestURL = 'https://blockchain.info/q/24hrprice';
    request(requestURL, function(error, response) {
      if(error) {
        console.log("got an error: " + error);
        next(error);
      } else {        
        price = response.body;
        logObject('the current bitcoin price: ' , price);
        // Respond to the user with the current temperature.
        //assistant.tell("The demo price is " + price);
      }
    });
  }

  getPrice(assistant); 

  var reponseText = 'The demo price is ' + price;

  // Leave conversation with SimpleResponse 
  assistant.intent(PRICE_ACTION, conv => {
    conv.close(new SimpleResponse({
     speech: responseText,
     displayText: responseText,
    })); 
  });

}); //End of app.post

// Handle errors.
app.use(function (err, req, res, next) {
  console.error(err.stack);
  res.status(500).send('Oppss... could not check the price');
})

// Pretty print objects for logging.
function logObject(message, object, options) {
  console.log(message);
  console.log(prettyjson.render(object, options));
}

// Listen for requests.
let server = app.listen(process.env.PORT || 3000, function () {
  console.log('Your app is listening on ' + JSON.stringify(server.address()));
});